The present invention relates to a Web server for transmitting a content to a client as a content request source in response to a content request from the client and, more particularly, to a method of allowing a server to retain/manage information related to the content currently displayed on a client.
In recent years, the World Wide Web (WWW) system for browsing information through a network, e.g., the Internet, has rapidly become popular. In the WWW, a client can browse contents called pages on a Web server (to be simply referred to as a server hereinafter) by using a content browsing mechanism (software in reality). This system is a so-called client server system in which a content request (generally called a page request) is output from a browser to a server, and the server searches and provides a content corresponding to the request.
In a conventional system, a client performs content browsing according to a procedure in which the client outputs a content request to a server, and the server transmits a content to the client. Every time an HTTP (Hyper Text Transfer Protocol) request is generated between a client and server, connection is made to a network. After the page contents are transmitted/received, disconnection is made. If network connection is always maintained, the load on the server increases. The above operation is therefore a means for preventing such a situation. However, since disconnection is made every time page contents are transmitted/received, connection must be performed independently. For this reason, the server has no means for acquiring information at the previous connection, e.g., information indicating which page has been previously requested.
The conventional system therefore uses a method of sending information at connection from a server to a client, storing it in the client, and reading out the information from the client at the next connection by using a function called xe2x80x9cCookiexe2x80x9d. In this method, however, information irrelevant to pages are sent to the client, posing problems in terms of security.
A web browser serving as an information browsing mechanism for a client is equipped with various operation buttons, e.g., a Back button (to return an immediately preceding page in a history), Forward button (to move to an immediately succeeding page in a history), and direct page selection button on a history display window. Page information subjected to operation using these buttons is generally stored in a browser cache. With the above button operation, therefore, page information intended by the user is generally extracted from the cache, but no access is made to the server. In this case as well, the server has no means for acquiring which page is currently displayed on the client.
Assume that link buttons are prepared in page information to make the user perform content browsing on the client side in the order intended by the server. In this case, if the user use the above operation buttons, content browsing may be performed in an order different from that intended by the server. This presents a problem in operation that attaches importance on the browsing order, e.g., Internet shopping and access to a database through an intranet.
Accordingly, it is an object of the present invention to provide a current display content information retention/management method in a server capable of retaining/managing the current display content information on a client.
It is another object of the present invention to provide a current display content information retention/management method in a server capable of designating the types of content information to be retained/managed.
It is still another object of the present invention to provide a current display content information retention/management method in a server capable of making a client perform content browsing in the order intended by the server.
It is still another object of the present invention to provide a current display content information retention/management method in a server capable of notifying a client of an operation error made by the client.
It is still another object of the present invention to provide a current display content information retention/management method in a server capable of re-transmitting the current display content information managed/retained by the server to a client, regardless of a request therefrom, when an operation error is made on the client side.
According to one aspect of the present invention, there is provided a method of allowing a Web server which transmits a content to a client as a content request source in accordance with a content request from the client to retain/manage information related to a content currently displayed on the client, comprising the steps of: preparing a current content storage list in which identification information of a latest content transmitted to the client as the content request source is registered in combination with client information indicating the client as the content request source; searching the current content storage list in response to the content request from the client by using the client information indicating the client as the content request source as a key, registering a set of the client information and identification information of a content indicated by the content request in the current content storage list when the client information of the content request source is not registered; and replacing the content identification information combined with the client information in the current content storage list with the content identification information indicated by the corresponding content request when the client information of the content request source is registered, and searching the content requested by the content request and transmitting the content to the client as the content request source.
The above method may further comprise the steps of: preparing a storage file type list in which types of content information to be registered in the current content storage list are registered; and searching the storage file type list with a type of the content information indicated by the content request as a key, and performing registration in the current content storage list only when the type of the content information indicated by the content request is registered in the storage file type list.
The above method may further comprise the steps of preparing a transmission order storage list in which an array indicating a content transmission order is registered, searching the transmission order storage list by using the content identification information indicated by the content request as a key, searching the current content storage list by using the client information of the corresponding content request source as a key when the array including the content identification information is present, and extracting content identification information combined with the client information when the client information of the content request source is registered; and searching the array for content identification information to be transmitted next to the extracted content identification information, searching for a content indicated by the content identification information when the searched content identification information coincides with the content identification information indicated by the content request, and performing registration processing in the current content storage list and the transmission processing.
The above method may further comprise the steps of: preparing a movement inhibition host list in which client information as a page movement inhibition target; setting, in a content transmitted from the Web server to the client as the content request source, a procedure for issuing a specific request from the client to the Web server to request page movement inhibition/permission when a predetermined portion of the content is operated while the content is displayed on the window; when the client issues a request to the Web server, checking whether the request is the specific request; when the request is the specific request, performing a first search to search the movement inhibition host list by using client information of the corresponding request source as a key; registering the client information in the movement inhibition host list when a result of the first search indicates that the client information of the request source is not registered, and the specific request indicates page movement inhibition, and deleting the client information from the movement inhibition host list when the client information of the request source is not registered, and the specific request indicates page movement permission; when the request is not the specific request, performing a second search to search the movement inhibition host list by using the client information of the request source as a key; when a result of the second search indicates that the client information of the request source is registered, returning an error notification to the client as the request source; and when a result of the second search indicates that the client information of the request source is not registered, searching for a content indicated by the request, and performing registration processing in the current content storage list and the transmission processing.
The above method may further comprise the steps of: preparing a movement inhibition host list in which client information as a page movement inhibition target; setting, in a content transmitted from the Web server to the client as the content request source, a procedure for issuing a specific request from the client to the Web server to request page movement inhibition/permission when a predetermined portion of the content is operated while the content is displayed on the window; when the client issues a request to the Web server, checking whether the request is the specific request; when the request is the specific request, performing a first search to search the movement inhibition host list by using client information of the corresponding request source as a key; registering the client information in the movement inhibition host list when a result of the first search indicates that the client information of the request source is not registered, and the specific request indicates page movement inhibition, and deleting the client information from the movement inhibition host list when the client information of the request source is not registered, and the specific request indicates page movement permission; when the request is not the specific request, performing a second search to search the movement inhibition host list by using the client information of the request source as a key; when a result of the second search indicates that the client information of the request source is registered, searching the current content storage list by using the client information of the request source as a key to acquire content identification information combined with the client information, and transmitting a content indicated by the acquired content identification information to the client as the request source in place of the requested content; and when a result of the second search indicates that the client information of the request source is not registered, searching a content indicated by the request and performing registration processing in the current content storage list and the transmission processing.
The above method may further comprise the step of: adding specific header information to a content to be transmitted to the request source, the information indicating that the content is not cached.
According to another aspect of the present invention, there is provided a Web server for transmitting a content to a client as a content request source in accordance with a corresponding content request from the client, comprising: a current content storage list in which identification information of a latest content transmitted to the client as the content request source is registered in combination with client information indicating the client as the content request source; registration means for searching the current content storage list in response to the content request from the client by using the client information indicating the client as the content request source as a key, registering a set of the client information and identification information of a content indicated by the content request in the current content storage list when the client information of the content request source is not registered; and replacing the content identification information combined with the client information in the current content storage list with the content identification information indicated by the corresponding content request when the client information of the content request source is registered, and means for searching the content requested by the content request and transmitting the content to the client as the content request source.
The Web server may further comprise a storage file type list in which types of content information to be registered in the current content storage list are registered.
The above Web server may further comprise a transmission order storage list in which an array indicating a content transmission order is registered.
The above Web server may further comprise a movement inhibition host list in which client information as a page movement inhibition target is registered.
The Web server may further comprise means for returning an error notification to the client as the request source when the client information of the request source is registered in the movement inhibition host list.
The Web server may further comprise means for, when the client information of the request source is registered in the movement inhibition host list, returning the same content as that currently displayed on the client as the request source to the client as the request source by searching the current content storage list.
In the Web server, specific header information indicting that a content is not cached may be added to the content to be transmitted to the request source.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.